The present invention is directed toward acetylenic imidazole compounds having central nervous activity. The compounds exhibit cholinergic agonists activity and are particularly useful for improving mental performance, glaucoma or treating mental deficiencies. As an example, Alzheimer's disease is a congenitive disorder characterized in part by a significant reduction in choline acetyltransferase activity, high affinity choline uptake and synthesis of acetylcholine in the forebrain areas which receive cholinergic input. The reduction in presynaptic markers of the forebrain cholinergic neurons is due to the degeneration of these neuronal pathways. Clinical observations indicate that the central cholinergic system may be involved in the physiology of cognitive functions. Thus there is a medical need for a cholinergic agonist which is likely to have therapeutic efficacy in cognitive disorders. Cholinergic agonists can also be useful as analgesics to treat pain.
Those compounds having cholinergic antagonist activity are useful in the treatment of extrapyramidal motor disorders. The central nervous system activity of the compounds also indicates that they can be useful in the treatment of disorders of the parasympathetic nervous system.
These compounds are related to cholinergic agonists oxotremorine [N-(4-pyrrolidino-2-butynyl)-pyrrolidin-2-one], which induces tremors and spasticity in laboratory animals by a cholinergic mechanism at extremely low doses. These undesirable side effects prevent the use of oxotremorine as a drug, and considerable effort has been directed to the preparation of related, clinically useful cholinergic agonists and antagonists.